Final answer:
Unipolarity or hegemony refers to a state of international relations dominated by a single power, known as a hegemon, which has overriding influence and can shape global order through its political, economic, and military capabilities.
Step-by-step explanation:
Unipolarity, or hegemony, in international relations is a condition often characterized by the dominance of a single state, known as a hegemon. This state has unrivaled political, economic, and military strength that it leverages to set and enforce the rules of the international system, often aligning other states with its own interests, cultures, and political structures. Promoting a unipolar system, the hegemon may use various strategies, from military intervention to institutional expansion, to maintain its position and extend its sphere of influence through trade and diplomacy.
Contrastingly, a bipolar system involves two approximately equal powers creating opposing spheres of influence, whereas a multipolar system comprises multiple states with smaller spheres, leading to a more distributed power structure. These systems are crucial in understanding the balance of power and the dynamics of international relations. Realism in political science describes how states focus on security and power, where hegemony plays a critical role in shaping global stability and order, especially in a unipolar world.
In essence, hegemony or unipolarity is the state of international relations where one country, by virtue of its superior capabilities, becomes capable of influencing or dictating global affairs, leading nations and their relationships with each other. This can create both stability and challenges, as seen in the post-Cold War era where the United States emerged as the global hegemon, responsible for providing support to less stable nations.